[Quantitative hepatitis B core antibody levels can be used as a predictive index of HBsAg clearance]

Objective: To explore the possibility of hepatitis B core antibody (anti-HBc) in predicting hepatitis B virus surface antigen (HBsAg) clearance. Methods: Sixty cases with chronic hepatitis B who were previously treated with peginterferon α-2a combined with nucleos(t)ide analogues (NAs) antiviral therapy were divided according to the HBsAg clearance or non-clearance; 41 cases in the clearance group and 19 cases in the non-clearance group. Double antigen sandwich method was used to detect patients anti-HBc quantitative levels during the course of treatment and at baseline, 24, 48, 72 and 96 weeks. Logistic regression analysis and receiver operating characteristic curve (ROC) were used to evaluate the predictive ability of related influencing factors for HBsAg clearance. Results: With antiviral treatment prolongation, anti-HBC quantitative levels in the overall population showed a progressive downward trend in the clearance group and the non-clearance group, but the anti-HBC level in the clearance group was significantly higher than non-clearance group at the baseline and successive detection time points during the antiviral treatment (P < 0.05). Multivariate logistic regression showed that baseline quantitative anti-HBC level, HBsAg decline at week 24 (log10 IU / ml), and alanine aminotransferase (ALT) > 1.5 times the upper limit of normal value (ULN) were all influencing factors for HBsAg clearance during the treatment (OR = 0.156, P = 0.026; OR = 0.134, P = 0.023; OR = 0.239, P = 0.028). Among them, the baseline quantitative anti-HBc level was the best independent predictor for HBsAg clearance (OR = 0.235; P = 0.004), and the sensitivity and specificity for predicting HBsAg clearance at > 3.40 log10 IU/ mL were 56.1% and 89.5%, respectively. Logistic regression model was used as a reference to construct combined predictors in order to improve the prediction accuracy. Among them, the combined factor 3 had the highest predictive value (the area under the ROC curve had reached up to 0.870; 95%CI was 0.781 ~ 0.960; P < 0.001). The cut-off value of combined factor 3 was > 0.386, and the sensitivity and specificity were 80.5% and 78.9%, respectively. In addition, the combined index had further improved the predictive value, which is the combination of any two or more indexes based on the baseline quantitative anti-HBC level, and HBsAg clearance predictive rate had reached 94.12% ~ 100%. Conclusion: The baseline quantitative anti-HBC level has the highest predictive value for HBsAg clearance. The combination of ALT > 1.5×ULN and HBsAg decline at 24 weeks during the treatment can more precisely predict HBsAg clearance. Therefore, it is a reliable non-invasive biomarker.